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How to use a 12v 4.5Ah battery to charge my phone?? Answered

ok, here is something similar to what I have.  I got mine as a spare battery from a garage door opener. 

12v 4.5 Ah battery

I would like to know how to build the easiest usb charger with this battery.  I would be charging a couple things at a time, a phone and what not.  would I be able to just take apart a 12v cigarette lighter charger and wire it to the terminals? 

thanks in advance

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5 years ago

It should work fine. I have done a video about how to use a charge a phone with a 9V battery using a car charger. They are nothing more than a small 12V to 9V switching buck converter, with a few bias resistors on the USB to enable the phone to charge faster.